1. Field of the invention
The present invention relates to an electronic still camera and, more particularly, to a twin head having two magnetic heads arranged side-by-side for recording and/or reproducing picture signal on a recording medium. The present invention also relates to a method for making such a twin head.
2. Description of the Prior Art
An electronic still camera uses a small size disc which has a plurality of tracks defined therein. One example of such a disc has a diameter of 2 inches and 50 coaxial tracks are formed on the disc. The disc is diagrammatically shown in FIG. 1. According to one standard, the tracks are very narrow such that the width of the track is 60 micrometers and the spacing between the tracks is 40 micrometers. The recording of one picture on the disc is effected either by using one track (field recording system) or two tracks (frame recording system). The present invention is particularly concerned with the frame recording system using two tracks for recording one picture.
In the frame recording system, which is also called a frame recording/reproducing system, a recording head of a twin head type is used. The recording head of twin head type is defined by two magnetic heads aligned side-by-side with a spacing of 40 micrometers and each magnetic head has the thickness of 60 micrometers.
For recording a picture on the disc, the disc makes one complete turn so as to record the picture signal on two neighboring tracks simultaneously. For reproducing the picture on a CRT, the picture signal recorded on one track is used for scanning odd lines and the picture signal recorded on the other track is used for scanning even lines.
A recording head having two magnetic heads aligned side-by-side is already known in the prior art, such as disclosed in Japanese Patent Publication (examined) No. 2647/1980 published Jan. 21, 1980. However, as disclosed in this Japanese Patent Publication No. 2647/1980, the prior art recording head with two magnetic heads is for the audio appliances or the like, and not for the electronic still camera. Also, the prior art recording head employs a non-magnetic plate sandwiched between two magnetic heads for the purpose of not only to separate the two heads but also to preventing the magnetic heads from the abrasion. This also implies that the prior art magnetic head of Japanese Patent Publication No. 2647/1980 is not for the electronic still camera.
Furthermore, unlike the recording heads used in the audio appliances or in video tape recorders, the recording head for the electronic still camera is very small. For example, the spacing between the two magnetic heads for the audio appliances is about a several hundred micrometers, whereas that of the twin head for the electronic still camera is 40 micrometers.
Thus, the two magnetic heads of twin head are positioned so close to each other that there arises a problem of a crosstalk between the two magnetic heads. The crosstalk is particularly outstanding between the faces of the magnetic heads which face the recording medium, i.e., the disc. As will be apparent from the description of the preferred embodiment, such a crosstalk can be suppressed by narrowing the width (which is in the direction parallel to the track tracing direction of the head) of the head chip.
The narrowing of the head chip width brings about another problem of difficulty in manufacturing such a small size recording head in a high accuracy particularly in its widthwise direction.